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SUMMARY:Primordial Black Holes and Gravitational Waves from Axion
DTSTART;VALUE=DATE-TIME:20240724T021000Z
DTEND;VALUE=DATE-TIME:20240724T023500Z
DTSTAMP;VALUE=DATE-TIME:20260512T213451Z
UID:indico-contribution-1271@indico.itp.ac.cn
DESCRIPTION:Speakers: Shuailiang Ge ()\nI present a new mechanism of primo
 rdial black hole (PBH) formation from QCD axion in the context of the Pecc
 ei-Quinn symmetry breaking during inflation. The axion string-wall network
  re-enters horizon sufficiently late\, so the closed domain walls that nat
 urally arise in the network are sufficiently large to collapse into PBHs. 
 Besides\, free axions from the collapse of open walls bounded by strings a
 ccount for dark matter. Intriguingly\, our PBHs can naturally explain the 
 gravitational microlensing events observed by the OGLE collaboration. In a
 ddition\, the collapse of string-wall network will release gravitational w
 aves (GWs)\, which is drastically different from that in the scaling regim
 e. For certain parameter space of axion-like particles\, such GW spectra c
 ould possibly account for the reported nHz stochastic GW background and ca
 n be tested by various GW interferometry experiments.\n\nhttps://indico.it
 p.ac.cn/event/244/contributions/1271/
LOCATION:
URL:https://indico.itp.ac.cn/event/244/contributions/1271/
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